U.S. patent number 5,376,477 [Application Number 08/231,890] was granted by the patent office on 1994-12-27 for storage battery and plate separator systems for a storage battery.
This patent grant is currently assigned to Teledyne Industries, Inc.. Invention is credited to Eugene I. Aidman, Galina Aidman, John E. James, Joseph A. Orsino.
United States Patent |
5,376,477 |
Aidman , et al. |
December 27, 1994 |
Storage battery and plate separator systems for a storage
battery
Abstract
A battery-plate separator system includes three layers in
face-to-face relationship, the first and third layers including a
porous mat of randomly oriented fibers, and, between the first and
third layers, a second layer comprising a porous organic polymeric
sheet with tortuosity and pores sufficiently small to substantially
block penetration by metallic particles. A storage battery includes
a plurality of positive lead peroxide elec-trodes, a plurality of
negative metallic lead electrodes, and the same three-layer
separator system in a closed case with a body of electrolyte to
which the system is inert, that is absorbed by the separator
system, and that is maintained in contact with the electrodes.
Inventors: |
Aidman; Eugene I. (Redlands,
CA), Aidman; Galina (Redlands, CA), Orsino; Joseph A.
(San Clemente, CA), James; John E. (Redlands, CA) |
Assignee: |
Teledyne Industries, Inc. (Los
Angeles, CA)
|
Family
ID: |
25521601 |
Appl.
No.: |
08/231,890 |
Filed: |
April 22, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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974102 |
Nov 10, 1992 |
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Current U.S.
Class: |
429/141; 429/142;
429/228; 429/225; 429/144 |
Current CPC
Class: |
H01M
50/449 (20210101); H01M 10/12 (20130101); Y02P
70/50 (20151101); Y02E 60/10 (20130101); H01M
2300/0005 (20130101) |
Current International
Class: |
H01M
2/16 (20060101); H01M 10/12 (20060101); H01M
10/06 (20060101); H01M 004/56 () |
Field of
Search: |
;429/141,144,142,225,228 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3005297 |
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Aug 1981 |
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DE |
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0010737 |
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Jan 1980 |
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JP |
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Primary Examiner: Willis, Jr.; Prince
Assistant Examiner: Nuzzolillo; M.
Parent Case Text
This application is a continuation of pending prior application
Ser. No. 07/974,102 filed Nov. 10, 1992, now abandoned.
Claims
What is claimed is:
1. A battery plate separator system having a size and shape
adequate to absorb and maintain electrolyte in contact with
adjacent electrodes in a lead-acid recombinant storage battery, and
to substantially completely separate all electrodes in said battery
from one another comprising at least three layers in face to face
relationship, the first and third layers comprising a porous
fibrous mat wherein the fibers are made of a material selected from
the group consisting of glass and organic polymers, and are
randomly oriented, each of said mats having a porosity greater than
90% and being inert to an aqueous electrolyte, when said
electrolyte is surfactant free, said first and third layers
maintaining said electrolyte substantially continuously in contact
with said electrodes in said lead-acid recombinant storage battery
and, between said first and said third layers, a second layer
comprising a porous organic polymeric sheet with a porosity in the
range of about 50% to about 65%, said porous organic polymeric
sheet being hydrophobic to said electrolyte, and having tortuosity
and pores sufficiently small to substantially block penetration by
metallic particulates that could attach to and grow on the negative
plates of a battery during charging of said battery.
2. The battery plate separator system of claim 1 wherein each of
said porous fibrous mats and said porous organic polymeric sheet
has a thickness and porosity sufficient to provide a storage
battery at a desired electrolyte saturation of separator pores with
a desired amount of electrolyte.
3. A lead-acid recombinant storage battery comprising a plurality
of positive lead peroxide electrodes and a plurality of negative
metallic lead electrodes in a closed case, and between each of said
electrodes, and substantially completely separating each of said
electrodes from one another, a three-layer separator system between
adjacent ones of said electrodes, and a body of an electrolyte to
which the separators are inert when said electrolyte is surfactant
free, and which is absorbed by said separator system and is
maintained in contact with each of the adjacent ones of said
electrodes, said separator system comprising at least three layers
in face-to-face relationship, the first and third layers comprising
a porous mat wherein the fibers are made of a material selected
from the group consisting of glass and organic polymers, and are
randomly oriented, each of said mats having a porosity greater than
90% and being inert to an aqueous electrolyte, when said
electrolyte is surfactant free, and, between said first and said
third layers, a second layer comprising a porous organic polymeric
sheet with a porosity in the range of about 50% to about 65%, said
porous organic polymeric sheet being hydrophobic to said
electrolyte, and having tortuosity and pores sufficiently small to
substantially block penetration by metallic particulates that could
attach to and grow on the negative plates of said battery during
charging of said battery.
4. The storage battery of claim 3 wherein each of said porous
fibrous mats and said porous organic polymeric sheet has a
thickness and porosity sufficient to provide said storage battery
at a desired electrolyte saturation of separator pores with a
desired amount of said electrolyte.
5. A method of making a recombinant storage battery, said method
including the steps of assembling a plurality of positive
electrodes comprising lead peroxide and a plurality of negative
electrodes comprising metallic lead with a separator system between
adjacent ones of each of the electrodes in a case having an opening
in at least one wall, introducing into said case a quantity of an
electrolyte sufficient to cover the electrodes, and to flood the
case, charging said battery, as necessary, removing from said case
electrolyte unabsorbed by said separators and said plates, and
closing the case, said separator system having a size and shape
sufficient to substantially completely separate each of said
electrodes from one another in said case and to absorb and maintain
said electrolyte in contact with adjacent electrodes in said
battery comprising at least three layers in face-to-face
relationship, the first and third layers comprising a porous mat
wherein the fibers are made of a material selected from the group
consisting of glass and organic polymers, and are randomly
oriented, each of said mats having a porosity greater than 90% and
being inert to an aqueous electrolyte, when said electrolyte is
surfactant free, and, between said first and said third layers, a
second layer comprising a porous organic polymeric sheet with a
porosity in the range of about 50% to about 65%, said porous
organic polymeric sheet being hydrophobic to said electrolyte, and
having tortuosity and pores sufficiently small to substantially
block penetration by metallic particulates that could attach to and
grow on the negative plates of said battery during charging of said
battery.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to storage batteries, particularly lead-acid
storage batteries, to plate separator systems for such batteries,
and to methods for producing such batteries and battery separator
systems.
BRIEF DESCRIPTION OF THE PRIOR ART
U.S. Pat. Nos. 3,362,861 and 3,159,508 disclose recombinant
batteries. U.S. Pat. No. 4,465,748 discloses a separator for
recombinant battery plates made of glass fibers of a plurality of
diameters or from mixtures of glass fibers and polypropylene
fibers. U.S. Pat. No. 4,216,280 discloses glass fiber sheet
material used as a plate separator in such a battery. U.S. Pat. No.
4,373,015 discloses sheet material for use as a separator in such a
battery in which the sheet material includes short staple fiber
polyester matting.
Sheet separators for use in non-recombinant batteries that include
glass fibers and organic fibers appear in U.S. Pat. Nos. 4,529,677;
4,363,856; 4,359,511; and 4,367,271. Japanese Patent Document
55/146872 discloses a battery separator material comprising glass
and organic fibers. U.S. Pat. No. 4,245,013 discloses a battery
plate separator that includes a first sheet of fibrous material and
polyethylene fibers, and a second sheet of fibrous material
including polyethylene and a synthetic pulp count higher than in
the first sheet.
None of these separators works well in storage batteries, and in
particular in lead-acid batteries that are substantially acid
limited and operate in acid-starved condition.
SUMMARY OF THE INVENTION
This invention relates to battery plate separator systems for use
in storage batteries, and in particular for use in recombinant
lead-acid batteries, that comprise at least three layers in each
system. The first and third layers comprise porous mats made of
randomly oriented, preferably non-woven, fibers. These fibers are
made of glass and/or of an organic polymeric material such as
polyethylene or polypropylene. These mats preferably have a
porosity of at least about 90%.
The second layer in this separator system, which lies between the
first and third layers, comprises a porous organic polymeric sheet.
Preferably, this sheet is made of a thermoplastic polymer such as
polyvinyl chloride, or a polyolefin such as polyethylene or
polypropylene. This sheet preferably has a porosity in the range of
about 50% to about 65%, and more preferably about 60%. This sheet
preferably has tortuosity and pores with a pore size sufficiently
small to block passage of lead dendrites.
Each of these three layers preferably also has a thickness
sufficient to provide a storage battery, at a desired electrolyte
saturation of separator pores, with a desired amount of the
electrolyte.
The invention also relates to storage batteries, such as
recombinant lead-acid batteries, that include a plurality of
positive and negative electrodes, such as lead peroxide and lead
electrodes, in a closed case; the new battery plate separator
system placed between adjacent electrodes; and an electrolyte to
which the separator system is inert, but that is absorbed by the
pores of the active materials and separators, and is maintained in
contact with adjacent electrodes in the battery.
The invention also comprises methods for producing storage
batteries, especially recombinant lead-acid batteries, that include
the steps of assembling a plurality of electrodes with the battery
plate separator systems of this invention between adjacent
electrodes in a case having an opening in at least one wall of the
case; introducing into the case sufficient electrolyte to cover the
electrodes; if desired, removing electrolyte that is not absorbed
by the separators, plates, or other internal surfaces that are
wetted by the electrolyte; and closing the case. If desired, the
case can be partially evacuated before the electrolyte is
introduced.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a perspective view, partially broken away, of a
battery including the preferred embodiment of the plate separator
system of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawing, a single cell battery 10 includes a
plurality of positive plates 12 that are electrically connected to
a positive terminal 14, and a plurality of negative plates 16
electrically connected to negative terminal 18. Plates 12 and 16
are housed within battery case 20. Boss 24 defines an opening in
the top surface of case 20. Between the plates is the separator
system of this invention comprising first and third layers 26. Each
of layers 26 is a porous mat made of randomly-oriented, non-woven
fibers. Between the first and third layers is a second layer 22
comprising a porous organic polymeric sheet. In one embodiment,
this three-layered separator system can be wrapped around all
plates of the same polarity in the battery. Alternatively, a part
of the separator system can be wrapped around each of the negative
plates, and the rest of the system around each of the positive
plates.
A preferred method for producing the battery depicted in FIG. 1
comprises the steps of filling battery case 20 containing dry
charged or unformed plates 12 and 16 and the separator system with
a quantity of electrolyte sufficient to flood the case and the
separators, forming the battery 10 by charging, if the plates are
unformed, and then sealing battery case 20 by inserting a cap (not
shown) into the opening defined by boss 24 to close battery 10.
The invention may be better understood from the following examples,
which are presented solely for illustrative purposes.
EXAMPLE 1
Two batteries, denoted A and B, were made with 17 electrodes each.
Each battery included 8 positive pasted plates made of lead
peroxide and 9 negative pasted plates made of metallic lead. Each
of these plates had a length of 4.25 inches, a height of 5.25
inches, and a thickness of 0.05 inch. Three-layer battery
separators were made from two porous fibrous mats having a length
of 10.75 inches, a width of 4.75 inches, and a thickness of 0.013
inch, and, between these two, a flat porous thermoplastic sheet
measuring 10.75 inches in length, 4.75 inches in width, and 0.010
inch in thickness. This separator system was wrapped around
adjacent plates in the battery. In particular, each of the positive
plates was wrapped with one of the porous fibrous mats folded
around the bottom of the plates. Each of the negative plates was
first wrapped with one of the porous fibrous mats, and then with a
sheet of the porous thermoplastic material around the bottom of the
plates. The porous non-woven fibrous mats were made of glass
fibers. The flat sheets of porous thermoplastic material were made
of polyethylene.
Two additional batteries, denoted C and D, were made which differed
from the first two batteries in that each separator system
contained only one porous fibrous mat having a thickness of 0.026
inch, instead of two layers of 0.013 inch each. One fibrous mat was
wrapped around each of the positive plates, and one sheet of porous
polyethylene sheet was wrapped around each of the negative plates.
In all other respects, batteries C and D were identical to the
batteries A and B.
All four of these batteries, A, B C, and D, were subjected to the
same internal compression during the course of the testing. Each of
the batteries contained the same electrolyte, namely sulfuric acid
solution. Each was conditioned electrically, characterized, and
sealed in the same way. Tests on these batteries produced the data
set forth in Table I:
TABLE I ______________________________________ CAPACITY
(Ampere-Hours) @ 100% DoD (DoD = Depth of Discharge; 100% DoD =
DISCHARGE Discharge to Final Voltage of 1.50 RATE Volts Per Cell)
(Amperes) A B C D ______________________________________ 30 27.62
29.68 28.16 31.01 30 30.44 32.84 31.43 32.52 30 30.54 32.81 30.77
32.48 30 31.11 31.25 28.55 30 31.32 60 28.49 26.67 28.55
______________________________________
Each of the cells was also subjected to a continuous life cycle
test that included the following three-step cycle: (a) discharging
at thirty amperes for one hour; (b) charging at 2.35 volts per cell
for four hours; and (c) resting, in open circuit condition, for one
hour. During the charging, the current was limited to 100 amperes.
In these tests, a cell failed, when, during discharge, the cell
voltage reached 1.50 volts within 1 hour. The results of these life
cycle tests appear in Table II below:
TABLE II ______________________________________ CYCLE NO. BATTERY
NO. BEFORE BATTERY FAILURE ______________________________________ A
97.sup.1 B 101.sup.2 C 18.sup. D 17.sup.
______________________________________ .sup.1 After cycle 65,
restrainers were removed On cycle 97, final discharge voltage was
1.84 V. .sup.2 After cycle 55, restrainers were reinstalled On
cycle 101, final discharge voltage was 1.87 V.
* * * * *